Spare a moment, please, for the lame-duck superpower. It calls itself the leader of the free world, but the free world no longer believes it. When it extends its hand, nobody rushes to accept. When it threatens, nobody trembles.After President Trump arrived in Beijing this week, Xi Jinping showered him with pomp befitting a summit of great powers. Yet the Chinese leader permitted potshots at his guest to go viral on his country’s internet rather than suppressing them, as some observers expected he would during a state visit. Xi answered Trump’s lavish praise by sternly lecturing him about meddling with Taiwan. In the end, Xi offered nothing of great substance—no solutions to the war in Iran, no sweeping trade deals, no promises of access to rare earth minerals. Xi used the visit to humor the lame-duck president, waiting for his time to pass.[Michael Schuman: A checkers player meets a three-dimensional-chess master]During the first Trump administration, foreign leaders flattered and accommodated the president out of deference to American power. They feared it; they relied on it. During the second administration, and especially since the beginning of the Iran war, their calculus has quietly shifted—not because the strategy of obsequiousness has failed, but because it’s no longer worth the trouble. Like many of his counterparts around the world, Xi has begun to assume that it’s not just Trump who is term-limited; it’s also his nation.Trump’s war in Iran was meant to showcase American power. It did the opposite. In the course of failing to remove a much weaker regime or eliminate its nuclear threat, the United States blew through its arsenal—so much so that allies in the Pacific reasonably wonder whether enough munitions remain to protect them. According to The Wall Street Journal, the Pentagon is now worried that it lacks the firepower to execute contingency plans for defending Taiwan.Supporters of the war argued that it would deal China a severe blow by eliminating one of its most potent allies. But the Gulf nations most threatened by Iran have actually turned to China. As first reported by The Washington Post, an intelligence assessment prepared for the chair of the Joint Chiefs of Staff warned that those countries have begun acquiring from Beijing the systems needed to protect their oil infrastructure and bases. Trump didn’t just fail to weaken China’s position in the Middle East. He strengthened it.Without exerting itself much, Beijing has profited from America’s self-immolation. China’s petroleum reserves and its investments in renewable energy have allowed it to offer Thailand, the Philippines, and Australia relief from the energy crisis that the United States instigated. Instead of applying diplomatic pressure on Iran to cut a deal, China has let the conflict linger, so that the United States continues to bear the blame for the disruptions to shipping. Meanwhile, China poses as the faithful steward of the rules-based order—the cooler head, the power on which even the U.S. must now rely.By patiently waiting out this moment, by letting the United States exhaust itself, China has bought time to pursue what Xi calls “national self-reliance”—time to catch up with the West technologically and to fortify itself for the point when competition takes a harsher turn.That very same strategy is guiding Iran. Trump repeatedly signals his desire for a deal to end the war, by wishfully exaggerating how close he is to reaching one. But Iran keeps responding to his offers with outrageous demands, including for reparations for the destruction the United States wrought.[Robert Kagan: America is now a rogue superpower]In the meantime, Iran has been able to dig out weapons systems buried in the rubble caused by American strikes on bunkers and caves. According to intelligence assessments, The New York Times reports, the Iranians have restored access to 30 out of 33 missile sites along the Strait of Hormuz. Across the whole of the country, Iran has regained roughly 90 percent of its underground missile storage. Without having to purchase a rocket or launcher, it has bounced back.American history is rife with the perils of lame-duck leaders. As their time in office grinds to a close, presidents grow eager to write a final chapter worthy of their saga. They reach for the grand gesture; they attempt to solve the intractable problem. But in their mad dash to assert their relevance, they manage merely to prove how little they matter to the rest of the world. Trump is now living that fate, and the consequences extend far beyond his presidency. Every failed deal, every summit that yields nothing, every boast that goes unfulfilled, confirms what adversaries already suspect. A lame-duck superpower exhausts itself in full view of the world, and the world moves on.